1. Field of the Invention
This invention relates to improvements in a method of producing a vehicle body structure reinforced by supplying a foamed resin therein, and in an arrangement for damming a flowable resin material of the foamed resin, to be used in the vehicle body structure producing method.
2. Description of the Prior Art
In the field of automotive industries, it is known that a foamed resin material such as foamed polyurethane resin is poured into confined spaces formed in an automotive vehicle body and is hardened within each confined space for the purpose of interrupting noise and vibration transmission, as disclosed in Japanese Patent Provisional Publication No. 61-116509. In connection with this, a damming arrangement has been proposed to dam the flowable resin material poured into the vehicle body at a desired position, as disclosed in Japanese Utility Model Publication No. 56-155975. In this damming arrangement, a part of a vehicle body panel (formed of steel plate) constituting a vehicle body pillar or the like is bent to form a dam wall of the shape corresponding to the cross-section of the pillar or the like. This dam wall blocks the inside space of the pillar or the like thereby to dam the flowing resin material poured into the inside space.
As mentioned above, many methods of pouring the foamed resin material into the confined space in the vehicle body are known; however, almost all the methods are intended to interrupt the transmission of noise and vibration. Accordingly, a relatively soft and low density foamed resin is used for the resin material to be filled in the confined space of the vehicle body. In this case, the foamed resin can be hardened in a desired location without using a reliable dam section.
In contrast, in case of using a relatively hard and high density foamed resin as the resin material for the purpose of reinforcing the vehicle body, the poured resin material unavoidably flows to unnecessary locations before hardening and therefore dam sections for the poured resin material is necessarily required.
If the above-mentioned damming arrangement including the dam wall formed by bending a part of vehicle body panel is employed, the end section of the vehicle body panels must be so formed bent as to correspond to the complicated cross-sectional shape of the vehicle body structure, thereby complicating the vehicle body panels thus increasing a production cost.
Additionally, when the vehicle body structure includes a generally vertically extending pillar, a water drain hose may be disposed within the pillar in an automotive vehicle provided with a sunroof. This makes it impossible to employ the above-discussed dam wall formed by bending a part of vehicle body panel. Additionally, if the confined space is defined by such a rigid dam wall (formed on steel plate) within the vehicle body structure, the rising pressure generated due to foaming of the resin material after being poured cannot be released thereby resulting in ejection of the resin material through a slight clearance at the joint of the panels.